Optical Interference Filters

Abstract

The optical interference filter includes a substrate and one or more sets of layers disposed on the substrate. Each set of layers includes a first layer including at least scandium, aluminum, and nitrogen, and a second layer including at least silicon and oxygen. The first layer may include at least one of a scandium aluminum nitride (ScAlN) material or a scandium aluminum nitroxide (ScAlNO) material. The second layer may include a silicon hydride (Si:H) material. An absolute value of the net stress of the one or more sets of layers may be less than or equal to 50 megapascals.

Description

[Technical field]

[0001] [CROSS-REFERENCE TO RELATED APPLICATIONS] This patent application claims priority to U.S. Provisional Patent Application No. 63 / 269,018, filed March 8, 2022, and entitled "OPTICAL INTERFERENCE FILTER," and U.S. Utility Patent Application No. 18 / 178,046, filed March 3, 2023, and entitled "OPTICAL INTERFERENCE FILTER," both of which are expressly incorporated by reference into this patent application. [Background technology]

[0002] An optical device can be utilized to capture information about the light. For example, the optical device can capture information associated with a set of wavelengths associated with the light. The optical device can include a set of sensor elements (e.g., optical sensors, spectroscopic sensors, and / or image sensors) that capture information. For example, an array of sensor elements can be utilized to capture information about multiple wavelengths. The array of sensor elements can be associated with an optical filter. The optical filter can include a passband associated with a first wavelength range of light passing through the array of sensor elements. The optical filter can be associated with blocking a second wavelength range of light passing through the array of sensor elements.

[0003] In some embodiments, an optical interference filter includes a substrate and a plurality of layer sets disposed on the substrate, the layers of each set including a first layer including at least scandium, aluminum, and nitrogen and a second layer including at least silicon and oxygen.

[0004] In some embodiments, the optical interference filter includes one or more sets of layers disposed on a substrate, each set of layers including a first layer including at least scandium, aluminum, and nitrogen and a second layer including at least silicon and oxygen.

[0005] In some embodiments, the wafer comprises a plurality of optical interference filters, each optical interference filter comprising a substrate and one or more sets of layers disposed on the substrate, each set of layers comprising a first layer comprising at least scandium, aluminum, and nitrogen and a second layer comprising at least silicon and oxygen. [Brief description of the drawings]

[0006] [Figure 1] FIG. 1 is a schematic diagram showing an overview of an embodiment described in this specification. [Diagram 2] 1 is a schematic diagram of an exemplary optical filter. [Diagram 3] FIG. 2 shows an example plot of the refractive index (n) of one or more layers comprising at least scandium, aluminum, and nitrogen, as described herein. [Figure 4] 1A-1C are example plots showing the transmission and angle shift performance of optical filters described herein. [Diagram 5] FIG. 1 is a schematic diagram of an exemplary wafer.

[0007] The detailed description of the embodiments below refers to the accompanying drawings. The same reference numbers in different drawings may indicate the same or similar elements. In the following description, a spectrometer is used as an example. However, the techniques, principles, procedures, and methods described herein can be used with any sensor, including but not limited to other optical and spectroscopic sensors. Summary of the Invention [Problem to be solved by the invention]

[0008] Optical filters can be fabricated by forming one or more layers on a substrate. For example, a conventional optical filter may include alternating layers of at least a first material, a second material, and a third material (e.g., alternating layers of silicon hydride (Si:H) material, silicon dioxide (SiO2) material, and tantalum pentoxide (Ta2O5) material) to allow the conventional optical filter to pass a threshold percentage of light (e.g., at least 65% of the light) associated with a particular spectral range (e.g., a spectral range of 800 to 1600 nanometers (nm)). However, forming alternating layers of at least three materials is complex and may result in low-quality layers that may introduce or propagate defects through the conventional optical filter. This may degrade the performance, manufacturability, and / or reliability of the conventional optical filter.

[0009] Furthermore, in many cases, the stress of each layer of one or more layers of a conventional optical filter is compressive (e.g., the stress of a layer is equal to or less than 0 megapascals (MPa)), which causes the stress (e.g., the total stress) of the one or more layers to be compressive. This can result in the conventional optical filter bowing (e.g., bending). This can cause one or more layers to experience coating spillage, which can affect the performance of the conventional optical filter. This can also cause the conventional optical filter to be more fragile (e.g., compared to a flat optical filter) and / or make the conventional optical filter more difficult to transport, handle, and / or use.

[0010] Additionally, the filter performance of conventional optical filters may degrade as the angle of incidence (AOI) of light directed at the optical filter changes from a set angle of incidence (e.g., 0 degrees (normal), 30 degrees, 45 degrees, etc.) to a threshold angle of incidence (e.g., deviation from the set angle of incidence greater than about 10 degrees, deviation from the set angle of incidence greater than about 20 degrees, and / or deviation from the set angle of incidence greater than 30 degrees). For example, conventional optical filters may shift to lower wavelengths as the angle of incidence increases. Thus, conventional optical filters may pass unwanted or undesired light, which may affect the detection accuracy of an optical sensor receiving the passed light. [Means for solving the problem]

[0011] The angular shift may be related to the effective refractive index of the optical filter (e.g., a bandpass filter). For example, the higher the effective refractive index, the smaller the angular shift. The effective refractive index can be calculated from the component refractive indices of the constituent materials of the optical filter. For example, the effective refractive index (n_eff) of an optical filter having mirrors formed from alternating layers of high and low refractive index constituent materials can be calculated at least in part based on an equation of the following set of forms:

number

number

number

number

[0012] The above equation shows that the higher the effective index, the smaller the angle shift of the filter. However, the effective index of the filter is limited to be less than the index of the highest index material in the filter (Equation 3).

[0013] Some embodiments described herein provide an optical filter including one or more sets of layers disposed on a substrate. Each set of layers may include a first layer including at least scandium, aluminum, and nitrogen (e.g., at least one of a scandium aluminum nitride (ScAlN) material or a scandium aluminum nitrogen oxide (ScAlNO) material), and a second layer including at least hydrogen and silicon (e.g., a silicon hydride (Si:H) material). In some embodiments, the optical filter passes a threshold percentage of light (e.g., at least 85% of the light) associated with a particular spectral range (e.g., a spectral range of 800-1600 nm). In this manner, the optical filter provides improved transmission performance over conventional optical filters. Furthermore, the optical filter only includes two alternating layers, thereby reducing the complexity associated with forming a set of layers. This reduces the likelihood of forming low quality layers, and thus the likelihood of defects being introduced or propagated within the optical filter. Thus, the performance, manufacturability, and / or reliability of the optical filter is improved over conventional optical filters.

[0014] In some implementations, the stress of the first layer may be configured to be tensile (e.g., 0 MPa or greater) when the stress of the second layer is compressive, or vice versa. In this manner, the amount of warping caused by one or more sets of layers disposed on the substrate may be minimized (e.g., by balancing the stress of the compressive layers and the stress of the tensile layers of the optical filter). For example, the first set of layers may include a tensile material and the second set of layers may include a compressive material, such that the net stress of the set of layers is approximately zero MPa (e.g., within tolerance). This minimizes the amount of warping of the optical filter and reduces coating runoff, thereby improving the performance of the optical filter (e.g., compared to conventional optical filters with warping). It may also improve the durability of the optical filter and / or make the optical filter easier to transport, handle, and / or use compared to conventional optical filters with warping.

[0015] Additionally, some embodiments described herein provide a low angle-shift optical filter with an effective refractive index that is greater than 95% of the refractive index of the highest refractive index material in the low angle-shift optical filter. For example, the low angle-shift optical filter can have an effective refractive index that takes the following form:

number

[0016] Additionally or alternatively, the low angle shift optical filter may have an effective refractive index that is 100% or more, 110% or more, 120% or more, and / or equal to the refractive index of the highest refractive index material of the low angle shift optical filter. In this manner, the low angle shift optical filter reduces the amount of unnecessary or undesirable light passing therethrough and improves the detection accuracy of an optical sensor that receives light passing through the low angle shift optical filter.

[0017] In some implementations, the first layer of the set or more layers includes at least scandium, aluminum, and nitrogen to provide control of the optical properties and stress of the first layer while maintaining the durability of the optical filter. For example, some materials (such as aluminum nitride (AlN) materials, binary tolerant materials, etc.) may be configurable to provide desired optical and stress properties, but may be below threshold durability for some combinations of optical and stress properties. In contrast, the use of ScAlN materials (ternary alloy materials) provides more flexibility in controlling optical properties, stress, and durability compared to binary alloy materials. For example, by manipulating the mole fraction of scandium (relative to aluminum) in ScAlN materials, the optical properties (such as refractive index) can be manipulated by changing the process conditions of deposition (e.g., sputtering) without significant changes in durability or stress properties. Thus, the flexibility and durability of the optical filter design is increased, and the integration complexity is reduced compared to binary alloys. For example, the optical properties of the sputtered ScAlN material can be adjusted, via composition, such that the ScAlN material composition substantially matches a Ta2O5 material with about 20% scandium (mole fraction), or such that the ScAlN material composition substantially matches a niobium tantalum oxide (NbTaO x ) material. By substituting the Ta2O5 material for the ScAlN material designed with the Si:H material, optical filters can be designed without the use of an interfacial SiO2 layer (which must be included to enhance the interface between layers, for example).

[0018] Additionally, the use of ScAlN materials allows the physical thickness of the layers to be controlled while maintaining the optical thickness of the layers. The optical thickness can be defined as the product of the physical thickness of the layer and the refractive index of the layer. The refractive index of ScAlN materials can be tuned by changing the mole fraction of scandium, which means that a constant optical thickness can be maintained at various layer thicknesses. This avoids the use of three or more layers of material or more complex designs, mitigates interface issues between layers, and provides for the use of thicker layers which are easier to manufacture than thinner layers. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] FIG. 1 is a schematic diagram showing an overview of an embodiment 100 described herein. As shown in FIG. 1, the embodiment 100 includes a sensor system 110. The sensor system 110 may be part of an optical system and may provide an electrical output corresponding to a sensor determination. The sensor system 110 includes an optical filter structure 120 including an optical filter 130, and an optical sensor 140. For example, the optical filter structure 120 may include an optical filter 130 that performs a passband filtering function. In another example, the optical filter 130 may be aligned with an array of sensor elements of the optical sensor 140.

[0020] Although some implementations described herein may be described in terms of optical filters within a sensor system, the implementations described herein may be used in other types of systems, external to a sensor system, or in other configurations.

[0021] As further shown in FIG. 1 and by reference numeral 150, an input optical signal is directed to the optical filter structure 120 at one or more angles of incidence θ. For example, input optical signals 150-1 and 150-2 may be directed to the optical filter structure 120 at angles of incidence θ (e.g., a set angle of incidence) and θ, respectively. The input optical signal may include, but is not limited to, light associated with a particular spectral range (e.g., a spectral range centered around 900 nm, such as a spectral range of 800 nm to 1000 nm, a spectral range of 800 nm to 1600 nm, a spectral range of 800 nm to 1100 nm, a spectral range of 1400 nm to 1600 nm, such as having a peak wavelength of 1550 nm, a spectral range of 500 nm to 5500 nm, or another spectral range). For example, an optical transmitter may direct light to the optical sensor 140 such that the optical sensor 140 can perform a measurement of the light. In other examples, the optical transmitter may direct light in different spectral ranges for different functions, such as testing functions, sensing functions, or communication functions, among other examples.

[0022] As further shown in FIG. 1 and by reference numeral 160, a first portion of the optical signal having a first spectral range does not pass through the optical filter 130 and the optical filter structure 120. For example, the dielectric filter stack of dielectric thin film layers, which may include high index material layers and low index material layers of the optical filter 130, may reflect, absorb, or cause the first portion of the light in a first direction. In this case, the first portion of the light may be a threshold portion of the light incident on the optical filter 130 that is not included in the band pass of the optical filter 130, for example, greater than 95% of the light that is not within a particular spectral range centered around 900 nm. As shown by reference numeral 170, a second portion of the optical signal passes through the optical filter 130 and the optical filter structure 120. For example, the optical filter 130 may pass a second portion of the light having a second spectral range in a second direction toward the optical sensor 140. In this case, the second portion of light may be a threshold portion of the light incident on optical filter 130 within the bandpass of optical filter 130, e.g., greater than 50% of the incident light in a spectral range centered at about 900 nm. The second portion of light may pass through optical filter 130 at or below a threshold angle shift, as described in more detail herein.

[0023] 1, based on the second portion of the optical signal passing to the optical sensor 140, the optical sensor 140 may provide an output electrical signal 180 for the sensor system 110, such as for use in imaging, sensing ambient light, detecting the presence of an object, performing a measurement, or facilitating communication. In some implementations, other arrangements of the optical filter 130 and the optical sensor 140 may be utilized. For example, rather than passing the second portion of the optical signal parallel to the input optical signal, the optical filter 130 may direct the second portion of the optical signal in another direction, toward an optical sensor 140 at another location.

[0024] As noted above, Figure 1 is provided as an example. Other implementations may differ from those described with respect to Figure 1.

[0025] 2 is a schematic diagram of an exemplary optical filter 200. In some implementations, the optical filter 200 may be an optical interference filter and / or may include at least one of a spectral filter, a multispectral filter, a bandpass filter, a blocking filter, a long wavelength pass filter, a short wavelength pass filter, a dichroic filter, a linear variable filter, a circular variable filter, a Fabry-Perot filter, a Bayer filter, a plasmonic filter, a photonic crystal filter, a nanostructure or metastructure filter, a focusing filter, a beam splitter, a polarizing beam splitter, a notch filter, an anti-reflective filter, a reflector, or a mirror, among other examples. FIG. 2 illustrates an example stackup of the optical filter 200.

[0026] As further shown in FIG. 2, the optical filter 200 may include a substrate 205 and one or more sets of layers 210 (e.g., one or more sets of optical filter layers). The substrate 205 may include a glass substrate, a polymer substrate, a polycarbonate substrate, a metal substrate, a silicon (Si) substrate, a germanium (Ge) substrate, or an active device wafer (e.g., including a photodiode (PD), a PD array, an avalanche photodiode (APD), an APD array, a charge-coupled device (CCD) sensor, and / or a complementary metal oxide semiconductor (CMOS) sensor, among other examples). In some implementations, the thickness of the substrate 205 may be 20 microns (μm), 50 μm, and / or 500 μm or more. Additionally or alternatively, the thickness of the substrate may be less than or equal to a certain thickness threshold. A particular thickness threshold may be, for example, 5 millimeters (mm) or less.

[0027] Of the one or more sets of layers 210, each set of layers 210 can include a first layer 215 and a second layer 220. The second layer 220 can be disposed (e.g., in a stack formation) on the first layer 215. In some embodiments, the second layer 220 can be disposed directly on the first layer 215. For example, as shown in FIG. 2A, a first surface (e.g., a lower surface) of the second layer 220 is disposed (e.g., directly) on a surface (e.g., an upper surface) of the first layer 215. Alternatively, one or more other layers can be disposed between the first layer 215 and the second layer 220.

[0028] In some implementations, one or more sets of layers 210 may be disposed on a single surface (e.g., a top surface) of substrate 205 (e.g., as shown in FIG. 2). Alternatively, when optical filter 200 includes multiple sets of layers 210 (e.g., two or more sets of layers 210), at least one set of layers 210 may be disposed on a first surface (e.g., a top surface) of substrate 205 and at least one other set of layers 210 may be disposed on a second surface (e.g., a bottom surface) of substrate 205.

[0029] The first layer 215 may include a first material including at least scandium, aluminum, and nitrogen. For example, the first material may include at least one of a scandium aluminum nitride (ScAlN) material or a scandium aluminum nitroxide (ScAlNO) material. The first material may additionally include one or more other elements or materials (e.g., scandium, aluminum, nitrogen, oxygen, hydrogen, an aluminum oxide (AlO) material, and / or an aluminum hydride (AlH) material). The second layer 220 may include a second material that may include at least one other material (e.g., at least one material other than the first material). The second material may be, among other examples, a silicon (Si) material, a silicon and hydrogen (SiH) material, a silicon hydride (Si:H) material, a silicon helium hydride (Si:He) material, a silicon nitrogen hydride (Si:HN) material, an amorphous silicon (α-Si) material, a silicon nitride (SiN) material, a germanium (Ge) material, a germanium hydride (Ge:H) material, a silicon germanium (SiGe) material, a silicon germanium hydride (SiGe:H) material, a silicon carbide (SiC) material, a silicon carbide hydride (SiC:H) material, a tantalum pentoxide (Ta2O5) material, a niobium pentoxide (Nb2O5) material, a niobium titanium oxide (NbTiO x ) material, niobium tantalum pentoxide (Nb 2-x Ta xThe second material may include a first material, such as a SiO2 (AlO5) material, a titanium oxide (TiO2) material, an aluminum oxide (Al2O3) material, a zirconium oxide (ZrO2) material, a yttrium oxide (Y2O3) material, or a hafnium oxide (HfO2) material, etc. In some embodiments, the second material may include at least hydrogen and silicon. For example, the second material may include a SiH material, a Si:H material, a Si:H-He material, and / or a Si:HN material, and in some embodiments, may additionally include one or more other elements and / or materials (e.g., a Si material, a SiN material, a Ge material, a Ge:H material, a SiGe material, and / or the like). Alternatively, in some embodiments, the second layer 220 may include a first material (e.g., a material including at least scandium, aluminum, and nitrogen), and the first layer 215 may include a second material (e.g., a material including at least one other material).

[0030] In some embodiments, each layer of the set of layers 210 is associated with a particular thickness. For example, the first layer 215 and the second layer 220 may each have a thickness between 2 and 2000 nm (e.g., a thickness between 2 nm and 2000 nm). In some embodiments, the first layer 215 and / or the second layer 220 may have a thickness between 2 nm and a thickness threshold (e.g., a thickness between 2 nm and a thickness threshold). The thickness threshold may be, for example, 4 nm, 6 nm, 8 nm, 10 nm, 15 nm, 20 nm, 30 nm, 40 nm, and / or 50 nm or less. Thus, the first layer 215 and / or the second layer 220 may be referred to as a "thin" layer if their respective thicknesses are equal to or less than the thickness threshold.

[0031] In some implementations, when optical filter 200 includes multiple sets of layers 210 (e.g., two or more sets of layers 210), the layers of the first set of layers 210 may have the same or different thicknesses as corresponding layers of the second set of layers 210. For example, the first layer 215 and the second layer 220 of the first set of layers 210 may have respective thicknesses that are the same (e.g., equal, within a threshold that may be 1 nm or less) and / or different from the corresponding thicknesses of the first layer 215 and the second layer 220 of the second set of layers 210.

[0032] Additionally, the thickness of each layer in the set of layers 210 and / or the number of the set or more layers 210 may be selected based on the intended set of optical properties of the optical filter 200, such as the intended passband, the intended transmittance, and / or another optical property. For example, the thickness of each layer in the set of layers 210 and / or the number of the set or more layers 210 may be selected such that the optical filter 200 can be used (e.g., transmit light as described above) in a spectral range of 800-1000 nm (e.g., from 800 nm to 1000 nm, with a center wavelength of about 900 nm), a spectral range of 800 nm to 1600 nm, a spectral range of 800 nm to 1100 nm, a spectral range of 1400 nm to 600 nm (e.g., with a peak wavelength of 1550 nm), a spectral range of 500-5500 nm, or another spectral range. In some implementations, the use of a first material including at least scandium, aluminum, and nitrogen allows for control of the thickness and / or number of layers while maintaining the optical properties of the optical filter 200. For example, by varying the mole fraction of the ScAlN material, the thickness of the layer can be varied while the refractive index of the layer including the ScAlN material is held constant, or vice versa. In this manner, the use of the first material provides flexibility in layer thickness while achieving desired optical properties at various layer thicknesses.

[0033] In some embodiments, the one or more sets of layers 210 may be configured to pass a threshold percentage of light associated with a particular spectral range. For example, the one or more sets of layers 210 may be configured to pass a threshold percentage of light associated with a spectral range of 800-1000 nm (e.g., having a center wavelength of about 900 nm). The threshold range may be, for example, 85%, 90%, 95%, and / or 99% or more. In some embodiments, for each layer (e.g., one of the first layer 215 or the second layer 220) of the one or more sets of layers 210 that includes a first material that includes at least scandium, aluminum, and nitrogen, the refractive index of the layer may be 2.2 to 2.4 for light having a wavelength of 500-5500 nm (e.g., light that is 500 nm or more and 5500 nm or less). The extinction coefficient of each layer that comprises the first material may be less than 0.001 for light having a wavelength of 500-5500 nm. Additionally or alternatively, for each layer (e.g., the other one of first layer 215 or second layer 220) in the set or more layers that includes at least one other material (e.g., a material other than at least scandium, aluminum, and nitrogen), the refractive index of the layer may be between 3.5 and 3.9 for light having a wavelength between 500 and 5500 nm.

[0034] In some implementations, the optical filter 200 can have an effective refractive index that is 95% or greater than the highest value of the first refractive index of the first layer 215 in the one or more sets of layers 210 and the second refractive index of the second layer 220 in the one or more sets of layers 210. For example, when the first layer 215 and the second layer 220 are arranged in a particular layer order (e.g., an alternating layer order of high and low refractive index layers), the first layer 215 and the second layer 220 can be sized to achieve an effective refractive index that is, for example, 95% or greater than the highest value of the first and second refractive indexes. In some implementations, the optical filter 200 can have an effective refractive index that is 100% or greater (e.g., up to 110%, 120%, 130%, 140%, or 150% of the highest value) of the first and second refractive indexes. Thus, for example, if the refractive index of second layer 220 is between 3.5 and 3.9, which is greater than the refractive index of first layer 215, the effective refractive index can be 3.7, 4.0, 4.5, 5.0, and / or 5.5 or greater.

[0035] In some embodiments, the stress (e.g., net stress) of the one or more set of layers 210 including a first material including at least scandium, aluminum, and nitrogen can be between −1000 MPa and 800 MPa (e.g., −1000 MPa to 800 MPa). Additionally or alternatively, the stress of each layer including the first material can be −1000 MPa to 800 MPa. That is, the stress of a particular layer (e.g., a particular first layer 215 or a particular second layer 220) including the first material in the one or more set of layers 210 can be between −1000 and 800 MPa, and the stress of another particular layer (e.g., another particular first layer 215 or another particular second layer 220) including the first material in the one or more set of layers 210 can be between −1000 and 800 MPa. The stress of a particular layer can be the same as the stress of another particular layer, or alternatively, can be different from the stress of another particular layer. For example, the stress in a particular layer may be tensile (eg, 0 MPa or greater) and the stress in another particular layer may be compressive (eg, less than 0 MPa), or vice versa.

[0036] In some implementations, the absolute value of the stress (e.g., net stress) of the one or more sets of layers 210 can be approximately zero (0) MPa (e.g., equal to 0 MPa within a tolerance, where the tolerance is 5 MPa or less). In some implementations, the absolute value of the stress (e.g., net stress) of the one or more sets of layers 210 may be approximately equal to a particular stress amount (e.g., equal to a particular stress amount within a tolerance, where the tolerance is 5 MPa or less). For example, the one or more sets of layers 210 may include a particular configuration of compressive and / or tensile materials such that the absolute value of the stress of the one or more sets of layers 210 is equal to a particular stress amount, which may be 50 MPa, 100 MPa, 200 MPa, 350 MPa, and / or 500 MPa or less, among other examples. Additionally or alternatively, the stress (e.g., net stress) of the set or more layers 210 may enable an amount of warping of the optical filter 200 to be equal to or less than a threshold percentage of a critical dimension (e.g., a maximum dimension such as one of the maximum width, maximum length, or maximum thickness of the optical filter 200) of the optical filter 200. For example, the set or more layers 210 may include a particular configuration of compressive and / or tensile materials such that the stress of the set or more layers 210 causes an amount of warping of the optical filter 200 (e.g., the difference between the maximum and minimum distances of a central surface of the optical filter 200 from a reference plane associated with one or more edges of the optical filter 200) to be equal to or less than 10% of the critical dimension of the optical filter 200. The threshold percentage may be, for example, equal to or less than 1%, 2%, 3%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, or 50%.

[0037] In some implementations, one or more other layers may be included in the optical filter 200, such as one or more protective layers, one or more capping layers (e.g., to provide environmental protection to the set or more layers 210), and / or one or more layers to provide one or more other filtering functionalities (e.g., a blocker or anti-reflection coating, among other examples). For example, in a single surface configuration, an additional layer (e.g., a capping layer), such as a dielectric layer (e.g., an oxide material such as a silicon dioxide (SiO2) material, a zirconium dioxide (ZrO2) material, and / or an yttrium oxide (Y2O3) material, a silicon nitride (Si3N4) material, a titanium nitride (TiN) material, and / or a zirconium nitride (ZrN) material, and / or another material that provides environmental protection), may be disposed on a surface (e.g., an upper surface) of the set or more layers 210. As another example, in a dual-surface configuration, a first additional layer may be disposed on a surface (e.g., a top surface) of a first portion of the set of layers 210 that is disposed on a surface (e.g., an upper surface) of the substrate 205, and a second additional layer may be disposed on a surface (e.g., a lower surface) of a second portion of the set of layers 210 that is disposed on another surface (e.g., a lower surface) of the substrate 205.

[0038] In some implementations, the set of layers 210 may be formed using a sputtering process. For example, the set of layers 210 may be formed by sputtering the first layer 215 and / or the second layer 220 (e.g., in an alternating layer order) onto the substrate 205 using a magnetron sputtering process (e.g., a pulsed magnetron sputtering process). In this manner, the optical filter 200 may be fabricated.

[0039] As noted above, Figure 2 is provided as an example. Other implementations may differ from those described with respect to Figure 2.

[0040] 3 is an example plot 300 of the refractive index (n) of one or more layers including at least scandium, aluminum, and nitrogen (e.g., at least one of a ScAlN material or a ScAlNO material) described herein. As shown in FIG. 3, for light having a wavelength of 500-2000 nm, the refractive index can be between 2.2-2.4.

[0041] As noted above, Figure 3 is provided as an example, other implementations may differ from those described with respect to Figure 3.

[0042] FIG. 4 is an example plot 400 illustrating the transmittance and angle shift performance of an optical filter 200 described herein. As shown in FIG. 4 and according to the solid line 410, the optical filter 200 may transmit more than 85% of light having a wavelength between 935-960 nm (with a peak of 97%) when the light has an angle of incidence of 0 degrees. As further shown in FIG. 4 and according to the dashed line 420, the optical filter 200 may transmit more than about 85% of light having a wavelength between 928-954 nm (with a peak of about 96%) when the light has an angle of incidence of 30 degrees. In some embodiments, the angle shift at the center wavelength of the optical filter 200 may be less than 1.0% of the center wavelength for angles of incidence between 0-30 degrees. For example, if the optical filter 200 is configured for a center wavelength of 940 nm, the optical filter 200 may have an angle shift of, for example, less than 9.4 nm at angles of incidence up to 30 degrees.

[0043] In some implementations, optical filter 200 may achieve a transmittance at the center wavelength that is greater than a transmittance threshold (e.g., of the peak transmittance of the optical filter at angles of incidence between 0 and 30 degrees), such as greater than 80%, greater than 85%, greater than 90%, and / or greater than 95%. Additionally, optical filter 200 may achieve a ripple of less than + / - 10%, less than + / - 5%, or less than + / - 1%, where ripple represents the deviation in transmittance across the passband at angles of incidence between 0 and 30 degrees.

[0044] As noted above, Figure 4 is provided as an example. Other implementations may differ from those described with respect to Figure 4.

[0045] 5 is a schematic diagram illustrating an overview of an example wafer 500. As shown in FIG. 5, the wafer may include a plurality of optical filters 200. The plurality of optical filters 200 may be formed on the wafer 500 using a sputtering process, such as a magnetron sputtering process, a singulation process (such as a dicing process), and / or another process. In some implementations, a threshold percentage of the plurality of optical filters 200 is free of singulation defects. The threshold percentage may be, for example, 50%, 55%, 75%, 85%, 95%, and / or 99% or more.

[0046] Optical filter 200 may include a singulation defect if an area on a surface (e.g., top surface) of optical filter 200 is chipped, delaminated, and / or otherwise damaged (e.g., as a result of the sputtering process and / or the singulation process) and the area is equal to or greater than a threshold size. The threshold size may be, for example, 0.001%, 0.00125%, 0.0025%, 0.0050%, 0.01%, 0.05%, 0.1%, 0.5% or more of the area of ​​the surface of optical filter 200. In some implementations, the threshold size may be, among other examples, 10 square microns (μm 2 ), 20μm 2 , 30μm 2 , 40μm 2 , and / or 50 μm 2 Thus, a threshold percentage of the plurality of optical filters 200 cannot contain damaged areas of greater than or equal to the threshold size.

[0047] The wafer 500 may include a threshold percentage of the optical filters 200 that do not include singulation defects for improved durability of the optical filters 200 due to each of the optical filters 200 including one or more sets of layers 210 described herein.

[0048] As noted above, Figure 5 is provided as an example, other implementations may differ from those described with respect to Figure 5.

[0049] The foregoing disclosure provides illustration and description, but is not intended to be exhaustive or to limit the embodiments to the precise forms disclosed. Modifications and variations may be made in light of the above disclosure or may be acquired from practice of the embodiments.

[0050] As used herein, satisfying a threshold can indicate that a value is greater than the threshold, greater than or equal to the threshold, less than the threshold, less than or equal to the threshold, equal to the threshold, not equal to the threshold, etc., depending on the context.

[0051] Even if certain combinations of features are disclosed in the claims and / or specification, these combinations are not intended to limit the disclosure of the various embodiments. Indeed, many of these features can be combined in ways not specifically described in the claims and / or specification. Although each dependent claim listed below may directly depend on only one claim, the disclosure of the various embodiments includes each dependent claim in combination with all other claims in the claim set. As used herein, language regarding "at least one" of a list of items refers to any combination of those items, including single elements. As an example, "at least one of a, b, or c" is intended to cover a, b, c, ab, ac, bc, and abc, as well as any combination with multiples of the same items.

[0052] No element, act, or instruction used herein should be construed as critical or essential unless expressly described as such. Also, as used herein, the articles "a" and "an" are intended to include one or more items and may be used interchangeably with "one or more." Additionally, as used herein, the article "the" is intended to include one or more items referenced in connection with the article "the" and may be used interchangeably with "the one or more." Additionally, as used herein, the term "set" is intended to include one or more items (e.g., related items, unrelated items, or a combination of related and unrelated items) and may be used interchangeably with "one or more." When only one item is intended, "only one" or similar language is used. Also, as used herein, terms such as "has," "have," "having," and the like are intended to be open-ended terms. Additionally, the phrase "based on" is intended to mean "based, at least in part, on," unless expressly stated otherwise. Also, as used herein, the term "or" when used in a series is intended to be inclusive and may be used interchangeably with "and / or" unless expressly stated otherwise (e.g., when used in combination with "either" or "only one of"). Additionally, spatially relative terms such as "below," "lower," "bottom," "above," "upper," "top," and the like may be used herein to describe the relationship of one element or feature to another element(s) or feature(s) as illustrated in the figures for ease of description.Spatially relative terms are intended to encompass different orientations of the apparatus, device, and / or element during use or operation in addition to the orientation depicted in the figures. The apparatus may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein may be interpreted accordingly.

[0053] As used herein, the term "X material" refers to at least a threshold percentage of X, where X is a chemical composition such as AlN, SiO2, or Si:H. The threshold percentage may be, for example, 1%, 5%, 10%, 25%, 50%, 75%, 85%, 90%, 95%, and / or 99% or more. Also, when a material is referred to by a specific chemical name or formula, the material may include non-stoichiometric variations of the stoichiometrically exact formula identified by the chemical name. For example, the scandium aluminum nitride (ScAlN) material described herein is represented by the formula ScxAl (1-x) N, where x is between 0 and 0.5.

Claims

1. 1. An optical interference filter, comprising: The substrate, as well as a plurality of sets of layers disposed on the substrate, each set of layers comprising: a first layer comprising at least scandium, aluminum, and nitrogen; and a second layer comprising at least silicon and oxygen; the set of layers comprising: An optical interference filter comprising:

2. 10. The optical interference filter of claim 1, wherein the first layer comprises at least one of a scandium aluminum nitride (ScAlN) material or a scandium aluminum nitrate (ScAlNO) material.

3. 10. The optical interference filter of claim 1, wherein the second layer comprises a silicon hydride (Si:H) material.

4. 10. The optical interference filter of claim 1, wherein the first layer has a thickness in the range of 2 nanometers to 40 nanometers.

5. 10. The optical interference filter of claim 1, wherein the set of layers is configured to pass a threshold percentage of light associated with a spectral range of 800 nanometers to 1000 nanometers, the threshold percentage of light being 85% or greater.

6. 2. The optical interference filter of claim 1, wherein at least one set of layers of the set of layers is disposed on a first surface of the substrate, and at least another set of layers of the set of layers is disposed on a second surface of the substrate.

7. 10. The optical interference filter of claim 1, wherein a surface of the first layer is disposed on a surface of the second layer.

8. 10. The optical interference filter of claim 1, wherein a net stress in the set of layers causes the optical interference filter to warp by no more than 3% of a critical dimension of the optical interference filter.

9. 1. An optical interference filter, comprising: one or more sets of layers disposed on the substrate, each set of layers comprising: a first layer comprising at least scandium, aluminum, and nitrogen; and a second layer comprising at least silicon and oxygen; 16. An optical interference filter comprising the one or more sets of layers comprising:

10. 10. The optical interference filter of claim 9, wherein the angular shift at the center wavelength of the optical interference filter is less than or equal to 1.0% of the center wavelength at angles of incidence between 0 and 30 degrees.

11. 11. The optical interference filter of claim 10, wherein the central wavelength is 940 nanometers.

12. 10. The optical interference filter of claim 9, wherein the absolute value of the net stress in the set or more layers causes the optical interference filter to warp by 10% or less of a critical dimension of the optical interference filter.

13. 10. The optical interference filter of claim 9, wherein the optical interference filter is configured to pass light associated with a spectral range of 800 to 1600 nanometers.

14. 10. The optical interference filter of claim 9, wherein the first layer has a first refractive index between 2.2 and 2.4 for light having a wavelength between 500 and 5500 nanometers, and the second layer has a second refractive index between 3.5 and 3.9 for light having a wavelength between 500 and 5500 nanometers.

15. 10. The optical interference filter of claim 9, wherein the first layer has a thickness in the range of 2 nanometers to 40 nanometers.

16. A wafer comprising a plurality of optical interference filters, each optical interference filter comprising: A substrate; and a plurality of sets of layers disposed on the substrate, each set of layers comprising: a first layer comprising at least scandium, aluminum, and nitrogen; and a second layer comprising at least silicon and oxygen; the set of layers comprising: The wafer includes:

17. 17. The wafer of claim 16, wherein the first layer has a thickness in the range of 2 nanometers to 40 nanometers.

18. 17. The wafer of claim 16, wherein the absolute value of the net stress in one or more of the sets of layers is less than 50 megapascals.

19. 17. The wafer of claim 16, wherein an angular shift in a center wavelength of the optical interference filters among the plurality of optical interference filters having an incident angle between 0 degrees and 30 degrees is 1.0% or less of the center wavelength.

20. 17. The wafer of claim 16, wherein one optical interference filter of the plurality of optical interference filters is configured to pass light associated with a spectral range of 800 to 1600 nanometers.

Images